import { type ClassValue, clsx } from "clsx"
import { twMerge } from "tailwind-merge"

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs))
}

export function formatDate(date: Date | string): string {
  const d = new Date(date)
  const now = new Date()
  const diff = now.getTime() - d.getTime()
  
  // Less than 1 minute
  if (diff < 60000) {
    return 'Just now'
  }
  
  // Less than 1 hour
  if (diff < 3600000) {
    const minutes = Math.floor(diff / 60000)
    return `${minutes}m ago`
  }
  
  // Less than 24 hours
  if (diff < 86400000) {
    const hours = Math.floor(diff / 3600000)
    return `${hours}h ago`
  }
  
  // Less than 7 days
  if (diff < 604800000) {
    const days = Math.floor(diff / 86400000)
    return `${days}d ago`
  }
  
  // More than 7 days
  return d.toLocaleDateString()
}

export function formatTime(date: Date | string): string {
  const d = new Date(date)
  return d.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })
}

export function formatFileSize(bytes: number): string {
  if (bytes === 0) return '0 Bytes'
  
  const k = 1024
  const sizes = ['Bytes', 'KB', 'MB', 'GB']
  const i = Math.floor(Math.log(bytes) / Math.log(k))
  
  return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i]
}

export function getFileIcon(mimeType: string): string {
  if (mimeType.startsWith('image/')) return '🖼️'
  if (mimeType.startsWith('video/')) return '🎥'
  if (mimeType.startsWith('audio/')) return '🎵'
  if (mimeType.includes('pdf')) return '📄'
  if (mimeType.includes('word')) return '📝'
  if (mimeType.includes('excel') || mimeType.includes('spreadsheet')) return '📊'
  if (mimeType.includes('powerpoint') || mimeType.includes('presentation')) return '📽️'
  if (mimeType.includes('zip') || mimeType.includes('rar') || mimeType.includes('archive')) return '📦'
  return '📎'
}

export function generateAvatar(name: string): string {
  const colors = [
    '#FF6B6B', '#4ECDC4', '#45B7D1', '#96CEB4', '#FFEAA7',
    '#DDA0DD', '#98D8C8', '#F7DC6F', '#BB8FCE', '#85C1E9'
  ]
  
  const initials = name
    .split(' ')
    .map(word => word[0])
    .join('')
    .toUpperCase()
    .slice(0, 2)
  
  const colorIndex = name.charCodeAt(0) % colors.length
  const color = colors[colorIndex]
  
  return `data:image/svg+xml,${encodeURIComponent(`
    <svg width="40" height="40" xmlns="http://www.w3.org/2000/svg">
      <circle cx="20" cy="20" r="20" fill="${color}"/>
      <text x="20" y="25" text-anchor="middle" fill="white" font-family="Arial" font-size="14" font-weight="bold">
        ${initials}
      </text>
    </svg>
  `)}`
}

export function debounce<T extends (...args: any[]) => any>(
  func: T,
  wait: number
): (...args: Parameters<T>) => void {
  let timeout: NodeJS.Timeout | null = null
  
  return (...args: Parameters<T>) => {
    if (timeout) {
      clearTimeout(timeout)
    }
    
    timeout = setTimeout(() => {
      func(...args)
    }, wait)
  }
}

export function throttle<T extends (...args: any[]) => any>(
  func: T,
  limit: number
): (...args: Parameters<T>) => void {
  let inThrottle: boolean
  
  return (...args: Parameters<T>) => {
    if (!inThrottle) {
      func(...args)
      inThrottle = true
      setTimeout(() => inThrottle = false, limit)
    }
  }
}

export function isValidEmail(email: string): boolean {
  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/
  return emailRegex.test(email)
}

export function isValidUsername(username: string): boolean {
  const usernameRegex = /^[a-zA-Z0-9_]{3,20}$/
  return usernameRegex.test(username)
}

export function truncateText(text: string, maxLength: number): string {
  if (text.length <= maxLength) return text
  return text.slice(0, maxLength) + '...'
}

export function copyToClipboard(text: string): Promise<void> {
  if (navigator.clipboard) {
    return navigator.clipboard.writeText(text)
  } else {
    // Fallback for older browsers
    const textArea = document.createElement('textarea')
    textArea.value = text
    document.body.appendChild(textArea)
    textArea.focus()
    textArea.select()
    
    try {
      document.execCommand('copy')
      return Promise.resolve()
    } catch (err) {
      return Promise.reject(err)
    } finally {
      document.body.removeChild(textArea)
    }
  }
}

export function downloadFile(url: string, filename: string): void {
  const link = document.createElement('a')
  link.href = url
  link.download = filename
  document.body.appendChild(link)
  link.click()
  document.body.removeChild(link)
}

export function isImageFile(file: File): boolean {
  return file.type.startsWith('image/')
}

export function isVideoFile(file: File): boolean {
  return file.type.startsWith('video/')
}

export function isAudioFile(file: File): boolean {
  return file.type.startsWith('audio/')
}

export function getInitials(name: string): string {
  return name
    .split(' ')
    .map(word => word[0])
    .join('')
    .toUpperCase()
    .slice(0, 2)
}